JPH0463916B2 - - Google Patents

Description

Detailed Description of the Invention The present invention utilizes viscoelasticity, which is a characteristic of viscoelastic bodies, to add sulfur absorbent to sulfur-containing liquid fuel.
The present invention relates to a method for stably dispersing particles with a size of 0.01 to 8 microns, which effectively exhibits this effect.

Here, when a high shear force is applied to a viscous substance, the property of deforming greatly while exhibiting stringiness is called viscoelasticity, and a substance that can exhibit this viscoelasticity is called a viscoelastic body. Asphalt, pitch etc. exhibit viscoelasticity in their original state, or
By the addition of simple auxiliary measures, such as mild heating or the addition of small amounts of liquids, such as compatible liquid oils, they can become viscous and therefore viscoelastic. . Furthermore, sulfur absorbent refers to a substance that combines with _SOx generated when sulfur-containing fuel is burned and captures it as a solid substance from the combustion gas. Inorganic compounds having bonding groups such as -OH, _-CO3 , =O, -OAC, etc. of heavy metals such as Ca, Mg, Ba, and Fe are mainly suitable.

"Characteristics of the Invention" The present inventor first added a solid organic substance to a viscoelastic material and kneaded it in such a way that the viscoelastic material was greatly deformed while exhibiting stringiness. We have discovered that the organic matter is pulverized finely and at the same time stably and uniformly dispersed in the viscoelastic body, and we have developed a method for its use.

Furthermore, in the present invention, by kneading inorganic sulfur absorbents such as Ca(OH) ₂ and CaCO ₃ in a viscoelastic state in a viscoelastic body, they are finely pulverized and uniformly dispersed in the viscoelastic body. It was found that it can be stably dispersed.

In addition, if an appropriate amount of water is present during kneading, water will exist at the interface between the finely dispersed sulfur absorbent and the viscoelastic body, and will not only help to promote the dispersion stability but also The present invention has been completed based on the discovery that the water dispersed in the fuel has an effective effect on the combustion of the fuel containing it, as will be described later.

“Problem to be solved by the present invention” Sulfur-containing hydrocarbons are used in bottom oil in the petroleum refining industry,
Like natural asphalt (bitumen), it exists in large quantities, and the former is mainly used for industrial purposes as C heavy oil, but the latter is almost unused despite its vast reserves.

As a method for effectively utilizing sulfur-containing substances, a flue gas desulfurization method was developed in Japan when C heavy oil is used for industrial purposes.

The flue gas desulfurization method involves absorbing _SOx in flue gas into water, oxidizing it, and then reacting with a sulfur absorbent
There are two methods: a method in which the sulfur content is extracted as a solid as CaSO ₄ , or a wet method in which the sulfur content is released as an aqueous solution as MgSO ₄ , and a sulfur absorbent is added to the fuel in advance and the _SOx generated during combustion is immediately removed using the sulfur absorber. , e.g. react with CaCO ₃ , Ca(OH) ₂ ,
Two dry methods are being considered to remove this as CaSO ₄ .

Technically speaking, the rate-limiting factor in the former is that _SOx in the flue gas is absorbed by water, and the amount of absorption is greater when the temperature of the water is lower. Generally, full gas is 350℃
At such high temperatures, it is necessary to lower the temperature of the absorption water in order to absorb the _SOx contained therein, resulting in a huge amount of water and large equipment, resulting in high equipment costs and variable costs.

Although the latter is an excellent process in theory, there is a problem in mixing the sulfur absorbent into the liquid oil. That is, no industrial method has yet been found for dispersing sulfur absorbents in liquid oil without settling them.

Ca(COOH) ₂ is water-soluble, and a method of stabilizing dispersed particles in liquid oil by using an aqueous solution in combination with a surfactant has been studied, but this method cannot compete with the wet method in terms of cost. Not used industrially.

In general, in the fuel premix flue gas desulfurization method, the desulfurization effect is said to be proportional to the reciprocal of the diameter of the sulfur absorbent dispersed in the fuel, and it is said that the desulfurization effect is proportional to the reciprocal of the diameter of the sulfur absorbent dispersed in the fuel. The success or failure of this method will be determined by whether it is possible to do so.

However, cheap CaCO ₃ and Ca(OH) ₂ are difficult to mechanically crush, and moreover, the crushed products tend to aggregate and form blocks during storage. Therefore, even if a crushed sulfur absorbent is added and dispersed in liquid oil, the associated particles will settle to the bottom of the liquid oil, or the remaining coarse particles will clog the holes in the burner tip during combustion, causing accidents. I become familiar with it.

Due to these difficulties, the former wet method is still used, even though the dry method is still not used industrially and is expensive.

The problem to be solved by the present invention is to solve the latter problem, that is, to overcome the current difficulties of the fuel premix desulfurization method and provide a method for industrially inexpensive and stable desulfurization, thereby increasing its use in the future. The aim is to create a means by which sulfur-containing fuel that cannot be obtained can be treated in the same way as non-sulfur-containing fuel.

"Means for Solving the Problem" The present invention aims to solve the problem of Ca(OH) in substances capable of exhibiting viscoelasticity such as asphalt pitch and coal tar pitch.
_2. When a sulfur absorbent such as CaCO ₃ or a small amount of water is added and kneaded, and the system is greatly deformed while exhibiting stringiness, the applied high shear force is efficiently transferred to the sulfur absorbent and water. This is to pulverize them finely and at the same time disperse and stabilize them uniformly in the system.

The sulfur absorbent or the sulfur absorbent and water become microparticles, which are surrounded by oil, and the microparticles associate as if only oil were present, and do not grow into large particles, that is, sulfur absorption. The agent and water/viscoelastic body form a stable dispersion state.

The sulfur absorbent dispersed in this viscoelastic body does not separate from the oil layer even after six months during oil storage at room temperature. To force this separation, a means such as heating or freezing is required to destroy the stable state of the sulfur absorbent and water/viscoelastic body.

In this way, we have created a new and useful method for making the sulfur absorbent fine and stably dispersing it by simply applying mechanical force by using a viscoelastic material and kneading it in a viscoelastic state. This is what I did.

This method uses a composition obtained by dispersing and mixing a sulfur absorbent in a viscoelastic body such as petroleum such as asphalt or a heavy fraction of coal such as coal tar pitch, or a composition obtained by dispersing and mixing the sulfur absorbent with a liquid oil such as light kerosene. Used as a mixture in the production of fuel.

Furthermore, by using the viscoelasticity of asphalt and coal tar pitch in advance, a mixed composition obtained by mixing and pulverizing these with coal or other organic substances is maintained in a state of retaining viscoelasticity, and these are used as a viscoelastic body. It can also be used in the present invention.

Further, as the substance used for addition or dilution, not only hydrocarbons such as light kerosene but also liquid organic substances such as alcohols can be used if there is an affinity. These operations generally do not impair the dispersion stability of the sulfur absorbent.

In addition, the presence of an appropriate amount of water accelerates the pulverization of the sulfur absorbent in the viscoelastic body, increases fuel efficiency, and further refines the sulfur absorbent during combustion, greatly increasing the desulfurization effect. It also plays a role.

Any method and apparatus may be used for kneading the viscoelastic body and the sulfur absorbent as long as it can apply a high shearing force to the mixture and can heat and cool the mixture as necessary.
A Banbury mixer, a kneader, etc. are effectively used.

In addition, when long-term stability of the dispersed state is required,
Partially saponified polyvinyl acetate as a dispersion stabilizer,
Partially higher fatty acid esters of polyvinyl alcohol are effectively used.

"Effects" The effects of sulfur absorbent and water upon combustion of fuel in which fine particles are stably dispersed will be explained.

A liquid oil that can be diluted with a liquid oil that has an affinity with this viscoelastic body in which this sulfur absorbent and water are stably dispersed is
Both have fuel suitability.

The former can be combusted in a combustion device with a double tube heating device, such as a Kracks device, and the latter can be combusted in a conventional furnace with air or steam atomization.

Water, which can also be used for the purpose of promoting the dispersion of sulfur absorbents, causes the combustion of the viscoelastic body or liquid oil containing the viscoelastic body to which it is added, to resemble the combustion of a gaseous body, resulting in the production of unburned carbon. Lose it.

At this time, the flue gas produced looks like white gas due to the dust. Further, almost no accumulation of ash due to the sulfur absorbent in the furnace after combustion was found.

Also, _SOx in the full gas from which dust has been removed
becomes undetectable when 1.2 molar equivalent of sulfur absorbent is added to S in fuel oil.

The collected dust is a fine white inorganic substance that is not colored by unburned carbon, and can be collected using a normal dust collector, such as a bag filter or a ventilator scrubber that uses water.

From this result, water mixed in fuel oil not only crushes liquid oil containing viscoelastic substances as if it were a gaseous body, but also It is presumed that the sulfur absorbent may also be crushed, increasing the reaction efficiency with _SOx .

"Effects of the Invention" The method of the present invention can be used to improve the production of fuels that have not yet been implemented due to the lack of finer sulfur absorbent and stabilization technology, compared to the conventionally industrialized and expensive flue gas desulfurization method. We solved these problems in the premix flue gas desulfurization method by using viscoelasticity to make the sulfur absorbent and water fine and stably dispersed in the viscoelastic body, creating a new, inexpensive and easy desulfurization method. developed.

The development of a simple and economical desulfurization method necessary for pollution control when using cheap or unused sulfur-containing heavy oil as a fuel is considered to have great industrial value.

The present invention will be explained below with reference to Examples.

Example 1 Asphalt commercial product (60/80, S content 5%)
While kneading 200 parts in a kneader at room temperature,
1.2 of CaCO ₃ crushed material per mole of S of asphalt
mol was added as a slurry dispersed in 20 parts of water.

In this system, as kneading progressed, the slurry showing a white band shape disappeared and became a black homogeneous phase. The particle size of the sulfur absorbent in this asphalt is 0.1
It was ~5 microns.

When this was diluted with 40 parts of light oil, it became completely homogeneous.

Example 2 Asphalt commercial product (60/80, S content 5%)
While kneading 200 parts in a kneader at room temperature,
One part of Ca(OH) ₂ in an amount equivalent to 1.2 moles per mole of S was slurried in 12 parts of water, and the paste was mixed therein.

This system became homogeneous after 2 minutes in a kneader, and 0.4 parts of partially saponified polyvinyl acetate (polymerization degree of 550) with a degree of saponification of 75 mol % was added and kneaded with respect to 1 part of added water. The system was completely homogeneous and 40 parts of kerosene was added to it.

This mixture has fluidity, and the particle size of the dispersion in this composition was 0.1 to 5 microns before addition of partially saponified polyvinyl acetate, but after addition, it was 0.01 to 1 micron, and in both cases. Also 1
Even after leaving it for a week, there was no change over time.

Example 3 The liquid oil of Example 1 was burned in a heating furnace at an oil refinery using a normal C heavy oil burner chip and 7 kg/cm ² G steam for atomization.

The shape of the flame is shown in Photo 1). This photo shows that the flames are strong, short, and spread horizontally, indicating complete combustion, as if gas fuel were used.

Next, the excess air ratio of the furnace was controlled to the same level as in normal operation, and a sample for _SOx measurement was taken from the middle of the chimney. At that time, the gas sample was passed through a stabilizing filter paper, and the amount of dust present in the flue gas and its hue were investigated.

A photograph of the filter paper is shown in Photo 2). As is clear from this photo, there are no suits or coke in the dust. Furthermore, from the amount of dust collected, it was confirmed that more than 95% of the sulfur absorbent that reacted during combustion was released into the atmosphere along with the flue gas.

The _SOx measured at this time was zero. In addition, this solid dust can be analyzed using an X-ray microanalyzer.
It was confirmed that it was _CaSO4 .

Photo 3) shows how the flue gas containing the reacted sulfur absorbent is released into the atmosphere from the chimney.

These dusts can be collected from the flue gas using bag filters, electrostatic precipitators, and ventilate scrubbers.

Furthermore, Photo 4) shows a microscopic photograph of the sulfur absorbent + water/asphalt produced by this method.

The particle size in this photo is less than 2 microns.

Example 4 Hot-rolled sludge generated at a steel factory contains 45% iron oxide (FeO, Fe ₂ O ₃ ), 50% water, and 5% palm oil.
% (each weight percent) is a yellow-red paste composition. A paste composition was added while kneading 200 parts of a commercial asphalt product (penetration 60/80, S content 5%) in a kneader at room temperature.
Added as Fe at a ratio of 1.2 mol to 1 mol of S,
Kneaded. As the kneading progressed, the yellow-red color of the paste disappeared and the kneaded product became a red-black homogeneous phase.
This mixture is fluid and has a mantle temperature of 200
Spray combustion was possible in a crack apparatus (p. 8 of this application) maintained at a temperature of .degree. The condition of the flame during combustion was the same as that shown in Example 3, and the solid matter adhering to the filter set in the _SO Ta. Also, the _SOx removal rate was 97%.

Claims (1)

[Claims] 1. A method for producing a liquid fuel, which uses a composition in which a sulfur absorbent is finely dispersed in a viscoelastic body such as asphalt or pitch.